Compounds of formula (I) Z-Ar.sub.1--Ar.sub.2 (I) wherein Z is a diazabicyclic amine, Ar.sub.1 is a 5- or 6-membered aromatic ring, and Ar.sub.2 is selected from the group consisting of an unsubstituted or substituted 5- or 6-membered heteroaryl ring; unsubstituted or substituted bicyclic heteroaryl ring; 3,4-(methylenedioxy)phenyl; carbazolyl; tetrahydrocarbazolyl; naphthyl; and phenyl; wherein the phenyl is substituted with 0, 1, 2, or 3 substituents in the meta- or para-positions. The compounds are useful in treating conditions or disorders prevented by or ameliorated by .alpha.7 nAChR ligands. Also disclosed are pharmaceutical compositions comprising compounds of formula (I) and methods for using such compounds and compositions.